Gabriel Campos-Martinez, 38, was charged Monday in the death of 66-year-old Hervey Medellin, whose head and several other body parts were found by a woman walking her dog in Hollywood's Griffith Park on January 17, 2012, according to the Los Angeles district attorney.

Campos-Martinez and Medellin shared a Hollywood apartment for about six months, Los Angeles County Deputy District Attorney Bobby Grace said.

A coroner concluded that Medellin had died as a result of asphyxiation and ruled the death a homicide, Grace said.

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Investigators have not revealed a motive for the gruesome killing, which police believe occurred around December 27, 2011.

A murder charge was filed on Monday against Campos-Martinez, who was arrested in San Antonio, Texas, Sunday. He is being held on $1 million bail and awaiting an extradition hearing.

The dog walker whose golden retriever, Ollie, discovered the head near a trail below the Hollywood sign said she at first thought the head was a movie prop.

"Our assumption was that there was always people filming up there, and it was a prop," Lauren Kornberg said in 2012. "We walked down the ravine and got closer and realized it was a freshly severed human head."

Cadaver dogs eventually found several hands and feet -- but no torso -- in the wooded area, which is near the home of actor Brad Pitt.